13518219792
由三個節點組成的 復制集 為網絡故障或是其他的系統故障提供了足夠的冗余。該復制集也有足夠的分布式讀操作的能力。復制集應該保持奇數個節點，這也就保證了 選舉 可以正常的進行
用3臺已有的 mongod 實例來部署一個由三個節點組成的 復制集
192.168.1.3 hadoop1.abc.com hadoop1
192.168.1.4 hadoop2.abc.com hadoop2
192.168.1.5 hadoop3.abc.com hadoop3
在生產環境中，我們應該將每個節點部署在獨立的機器上，并使用標準的MongoDB端口 27017 。使用 bind_ip 參數來限制訪問MongoDB的應用程序的地址。
若使用了異地分布式架構的復制集，請確保多數 mongod 實例節點位于主數據中心中。
確保各個節點之間可以正常通訊，且各個客戶端都處于安全的可信的網絡環境中。可以考慮以下事項：
建立虛擬的專用網絡。確保各個節點之間的流量是在本地網絡范圍內路由的。（Establish a virtual private network. Ensure that your network topology routes all traffic between members within a single site over the local area network.）
配置連接限制來防止未知的客戶端連接到復制集。
配置網絡設置和防火墻規則來對將MongoDB的端口僅開放給應用程序，來讓應用程序發的進出數據包可以與MongoDB正常交流。
最后請確保復制集各節點可以互相通過DNS或是主機名解析。我們需要配置DNS域名或是設置 /etc/hosts 文件來配置。
這里實驗，是關閉防火墻，并把selinux設置成setenforce 0
系統環境如下：
[root@hadoop2 data]# cat /etc/issue CentOS release 6.5 (Final) Kernel \r on an \m [root@hadoop2 data]# uname -r 2.6.32-431.el6.x86_64配置文件選項：
port = 27017
bind_ip =
dbpath =
fore = true
replSet = testrs0
rest = true
1、建立每個節點都建立據據目錄
[root@hadoop1 ~]# mkidr -pv /mongodb/data/ [root@hadoop1 ~]# chown mongod.mongod /mongodb/data/2
在每個節點上啟動 mongod 并通過制定 replSet 參數來指定其復制集名，并可以指定其他需要的參數
[root@hadoop1 ~]# vim /etc/mongod.conf //添加如下 #Replica Set replSet = testrs0 或者 [root@hadoop1 ~]# mongod --replSet "testrs0"確保每個節點都有相同復制集名稱
[root@hadoop1 ~]# scp /etc/mongod.conf root@hadoop2:/etc/;scp /etc/mongod.conf root@hadoop2:/etc/;
注意了，如果解決啟動mongod 時，出現addr already in use錯誤，原因啟動端口被占用
[root@hadoop1 data]# mongod 2015-07-29T19:15:51.728+0800 E NETWORK [initandlisten] listen(): bind() failed errno:98 Address already in use for socket: 0.0.0.0:27017 2015-07-29T19:15:51.728+0800 E NETWORK [initandlisten] addr already in use 2015-07-29T19:15:51.729+0800 I STORAGE [initandlisten] exception in initAndListen: 29 Data directory /data/db not found., terminating 2015-07-29T19:15:51.729+0800 I CONTROL [initandlisten] dbexit: rc: 100把端口找出來，kill掉
[root@hadoop1 ~]# netstat -anp|more unix 2 [ ACC ] STREAM LISTENING 15588 2174/mongod /tmp/mongodb-27017.sock[root@hadoop1 ~]# kill 2174 [root@hadoop1 ~]# /etc/init.d/mongod start Starting mongod: [確定][root@hadoop1 ~]# mongo
//使用rs.initiate()命令，MongoDB將初始化一個由當前節點構成、擁有默認配置的復制集。
> rs.initiate() { "info2" : "no configuration explicitly specified -- making one", "me" : "hadoop1.abc.com:27017", "info" : "try querying local.system.replset to see current configuration", "ok" : 0, "errmsg" : "already initialized", "code" : 23 } > rs.status() { "state" : 10, "stateStr" : "REMOVED", "uptime" : 38, "optime" : Timestamp(1438168698, 1), "optimeDate" : ISODate("2015-07-29T11:18:18Z"), "ok" : 0, "errmsg" : "Our replica set config is invalid or we are not a member of it", "code" : 93 }查看日志 文件
2015-07-29T20:00:45.433+0800 W NETWORK [ReplicationExecutor] Failed to connect to 192.168.1.3:27017, reason: errno:111 Connection refused
2015-07-29T20:00:45.433+0800 W REPL [ReplicationExecutor] Locally stored replica set configuration does not have a valid entry for the current node; waiting for reconfig or remote heartbeat; Got "NodeNotFound No host described in new configuration 1 for replica set testrs0 maps to this node" while validating { _id: "testrs0", version: 1, members: [ { _id: 0, host: "hadoop1.abc.com:27017", arbiterOnly: false, buildIndexes: true, hidden: false, priority: 1.0, tags: {}, slaveDelay: 0, votes: 1 } ], settings: { chainingAllowed: true, heartbeatTimeoutSecs: 10, getLastErrorModes: {}, getLastErrorDefaults: { w: 1, wtimeout: 0 } } }
2015-07-29T20:00:45.433+0800 I REPL [ReplicationExecutor] New replica set config in use: { _id: "testrs0", version: 1, members: [ { _id: 0, host: "hadoop1.abc.com:27017", arbiterOnly: false, buildIndexes: true, hidden: false, priority: 1.0, tags: {}, slaveDelay: 0, votes: 1 } ], settings: { chainingAllowed: true, heartbeatTimeoutSecs: 10, getLastErrorModes: {}, getLastErrorDefaults: { w: 1, wtimeout: 0 } } }
2015-07-29T20:00:45.433+0800 I REPL [ReplicationExecutor] This node is not a member of the config
2015-07-29T20:00:45.433+0800 I REPL [ReplicationExecutor] transition to REMOVED
2015-07-29T20:00:45.433+0800 I REPL [ReplicationExecutor] Starting replication applier threads
2015-07-29T20:00:49.067+0800 I NETWORK [initandlisten] connection accepted from 127.0.0.1:58852 #1 (1 connection now open)
2015-07-29T20:01:17.436+0800 I COMMAND [conn1] replSet info initiate : no configuration specified. Using a default configuration for the set
2015-07-29T20:01:17.436+0800 I COMMAND [conn1] replSet created this configuration for initiation : { _id: "testrs0", version: 1, members: [ { _id: 0, host: "hadoop1.abc.com:27017" } ] }
2015-07-29T20:01:17.436+0800 I REPL [conn1] replSetInitiate admin command received from client
5、將其他的節點加入復制集。
通過 rs.add() 來將剩下的節點加入復制集。
testrs0:PRIMARY> rs.add("192.168.1.4:27017") { "ok" : 1 } testrs0:PRIMARY> rs.status() { "set" : "testrs0", "date" : ISODate("2015-07-30T02:09:45.871Z"), "myState" : 1, "members" : [ { "_id" : 0, "name" : "hadoop1.abc.com:27017", "health" : 1, "state" : 1, "stateStr" : "PRIMARY", "uptime" : 50410, "optime" : Timestamp(1438222179, 1), "optimeDate" : ISODate("2015-07-30T02:09:39Z"), "electionTime" : Timestamp(1438171776, 1), "electionDate" : ISODate("2015-07-29T12:09:36Z"), "configVersion" : 2, "self" : true }, { "_id" : 1, "name" : "192.168.1.4:27017", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 6, "optime" : Timestamp(1438222179, 1), "optimeDate" : ISODate("2015-07-30T02:09:39Z"), "lastHeartbeat" : ISODate("2015-07-30T02:09:45.081Z"), "lastHeartbeatRecv" : ISODate("2015-07-30T02:09:45.183Z"), "pingMs" : 1, "configVersion" : 2 } ], "ok" : 1 }testrs0:PRIMARY> rs.add("192.168.1.5:27017") { "ok" : 1 } testrs0:PRIMARY> rs.status() { "set" : "testrs0", "date" : ISODate("2015-07-30T02:28:52.382Z"), "myState" : 1, "members" : [ { "_id" : 0, "name" : "hadoop1.abc.com:27017", "health" : 1, "state" : 1, "stateStr" : "PRIMARY", "uptime" : 51557, "optime" : Timestamp(1438223187, 1), "optimeDate" : ISODate("2015-07-30T02:26:27Z"), "electionTime" : Timestamp(1438171776, 1), "electionDate" : ISODate("2015-07-29T12:09:36Z"), "configVersion" : 3, "self" : true }, { "_id" : 1, "name" : "192.168.1.4:27017", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 1153, "optime" : Timestamp(1438223187, 1), "optimeDate" : ISODate("2015-07-30T02:26:27Z"), "lastHeartbeat" : ISODate("2015-07-30T02:28:52.337Z"), "lastHeartbeatRecv" : ISODate("2015-07-30T02:28:50.438Z"), "pingMs" : 0, "syncingTo" : "hadoop1.abc.com:27017", "configVersion" : 3 }, { "_id" : 2, "name" : "192.168.1.5:27017", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 13, "optime" : Timestamp(1438223187, 1), "optimeDate" : ISODate("2015-07-30T02:26:27Z"), "lastHeartbeat" : ISODate("2015-07-30T02:28:50.437Z"), "lastHeartbeatRecv" : ISODate("2015-07-30T02:28:50.478Z"), "pingMs" : 1, "configVersion" : 3 } ], "ok" : 1 } testrs0:PRIMARY> rs.isMaster() { "setName" : "testrs0", "setVersion" : 3, "ismaster" : true, "secondary" : false, "hosts" : [ "hadoop1.abc.com:27017", "192.168.1.4:27017", "192.168.1.5:27017" ], "primary" : "hadoop1.abc.com:27017", "me" : "hadoop1.abc.com:27017", "electionId" : ObjectId("55b8c280790a6c1f967f6147"), "maxBsonObjectSize" : 16777216, "maxMessageSizeBytes" : 48000000, "maxWriteBatchSize" : 1000, "localTime" : ISODate("2015-07-30T02:30:18Z"), "maxWireVersion" : 3, "minWireVersion" : 0, "ok" : 1 }其他節點hadoop2驗證一下
testrs0:SECONDARY> rs.isMaster() { "setName" : "testrs0", "setVersion" : 3, "ismaster" : false, "secondary" : true, "hosts" : [ "hadoop1.abc.com:27017", "192.168.1.4:27017", "192.168.1.5:27017" ], "primary" : "hadoop1.abc.com:27017", "me" : "192.168.1.4:27017", "maxBsonObjectSize" : 16777216, "maxMessageSizeBytes" : 48000000, "maxWriteBatchSize" : 1000, "localTime" : ISODate("2015-07-30T02:32:43.546Z"), "maxWireVersion" : 3, "minWireVersion" : 0, "ok" : 1 }6、在主節點上創建數據，從節點是否獲取到
testrs0:PRIMARY> use testdb switched to db testdb testrs0:PRIMARY> db.testcoll.insert({Name: "test",Age: 50,Gender: "F"}) WriteResult({ "nInserted" : 1 }) testrs0:PRIMARY> db.testcoll.find() { "_id" : ObjectId("55b9945b92ad0ab98483695e"), "Name" : "test", "Age" : 60, "Gender" : "F" } { "_id" : ObjectId("55b994ce92ad0ab98483695f"), "Name" : "test", "Age" : 50, "Gender" : "F" }在從節點上查詢，是不可以直接查詢，要使用一個命令rs.slave()把自己提升為從節點
testrs0:SECONDARY> rs.slaveOk() testrs0:SECONDARY> use testdb; switched to db testdb testrs0:SECONDARY> db.testcoll.find() { "_id" : ObjectId("55b9945b92ad0ab98483695e"), "Name" : "test", "Age" : 60, "Gender" : "F" } { "_id" : ObjectId("55b994ce92ad0ab98483695f"), "Name" : "test", "Age" : 50, "Gender" : "F" }7、讓主節點hadoop1掛掉
[root@hadoop1 data]# service mongod stop Stopping mongod:在hadoop3驗證一下
testrs0:PRIMARY> rs.status() { "set" : "testrs0", "date" : ISODate("2015-07-30T04:36:19.677Z"), "myState" : 1, "members" : [ { "_id" : 0, "name" : "hadoop1.abc.com:27017", "health" : 0, "state" : 8, "stateStr" : "(not reachable/healthy)", "uptime" : 0, "optime" : Timestamp(0, 0), "optimeDate" : ISODate("1970-01-01T00:00:00Z"), "lastHeartbeat" : ISODate("2015-07-30T04:36:19.503Z"), "lastHeartbeatRecv" : ISODate("2015-07-30T04:33:18.147Z"), "pingMs" : 0, "lastHeartbeatMessage" : "Failed attempt to connect to hadoop1.abc.com:27017; couldn't connect to server hadoop1.abc.com:27017 (192.168.1.3), connection attempt failed", "configVersion" : -1 }, { "_id" : 1, "name" : "192.168.1.4:27017", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 7661, "optime" : Timestamp(1438225614, 1), "optimeDate" : ISODate("2015-07-30T03:06:54Z"), "lastHeartbeat" : ISODate("2015-07-30T04:36:19.335Z"), "lastHeartbeatRecv" : ISODate("2015-07-30T04:36:19.348Z"), "pingMs" : 0, "configVersion" : 3 }, { "_id" : 2, "name" : "192.168.1.5:27017", "health" : 1, "state" : 1, "stateStr" : "PRIMARY", "uptime" : 7664, "optime" : Timestamp(1438225614, 1), "optimeDate" : ISODate("2015-07-30T03:06:54Z"), "electionTime" : Timestamp(1438230801, 1), "electionDate" : ISODate("2015-07-30T04:33:21Z"), "configVersion" : 3, "self" : true } ], "ok" : 1 } testrs0:PRIMARY> db.isMaster() { "setName" : "testrs0", "setVersion" : 3, "ismaster" : true, "secondary" : false, "hosts" : [ "hadoop1.abc.com:27017", "192.168.1.4:27017", "192.168.1.5:27017" ], "primary" : "192.168.1.5:27017", "me" : "192.168.1.5:27017", "electionId" : ObjectId("55b9a91100e446910c89a0a3"), "maxBsonObjectSize" : 16777216, "maxMessageSizeBytes" : 48000000, "maxWriteBatchSize" : 1000, "localTime" : ISODate("2015-07-30T04:37:33.090Z"), "maxWireVersion" : 3, "minWireVersion" : 0, "ok" : 1 } testrs0:PRIMARY> db.testcoll.insert ({Name: "tom",Age: 45,Gender: "G"}) WriteResult({ "nInserted" : 1 })回到hadoop2查看一下數據
testrs0:SECONDARY> db.testcoll.find() { "_id" : ObjectId("55b9942d92ad0ab98483695c"), "Name" : "test", "Age" : 60, "Gender" : "F" } { "_id" : ObjectId("55b9944892ad0ab98483695d"), "Name" : "test", "Age" : 60, "Gender" : "F" } { "_id" : ObjectId("55b9945b92ad0ab98483695e"), "Name" : "test", "Age" : 60, "Gender" : "F" } { "_id" : ObjectId("55b994ce92ad0ab98483695f"), "Name" : "test", "Age" : 50, "Gender" : "F" } { "_id" : ObjectId("55b9aa714b575261aff42f25"), "Name" : "tom", "Age" : 45, "Gender" : "G" }讓hadoop1上線
[root@hadoop1 data]# service mongod start Starting mongod:再驗證一下狀態，但不能奪回主動權，除非讓它優先級高一點。
這種場景下，它自動成為從的了
testrs0:SECONDARY> rs.status() { "set" : "testrs0", "date" : ISODate("2015-07-30T04:44:16.534Z"), "myState" : 2, "syncingTo" : "192.168.1.4:27017", "members" : [ { "_id" : 0, "name" : "hadoop1.abc.com:27017", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 165, "optime" : Timestamp(1438231153, 1), "optimeDate" : ISODate("2015-07-30T04:39:13Z"), "syncingTo" : "192.168.1.4:27017", "configVersion" : 3, "self" : true }, { "_id" : 1, "name" : "192.168.1.4:27017", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 164, "optime" : Timestamp(1438231153, 1), "optimeDate" : ISODate("2015-07-30T04:39:13Z"), "lastHeartbeat" : ISODate("2015-07-30T04:44:16.199Z"), "lastHeartbeatRecv" : ISODate("2015-07-30T04:44:15.824Z"), "pingMs" : 0, "syncingTo" : "192.168.1.5:27017", "configVersion" : 3 }, { "_id" : 2, "name" : "192.168.1.5:27017", "health" : 1, "state" : 1, "stateStr" : "PRIMARY", "uptime" : 164, "optime" : Timestamp(1438231153, 1), "optimeDate" : ISODate("2015-07-30T04:39:13Z"), "lastHeartbeat" : ISODate("2015-07-30T04:44:16.185Z"), "lastHeartbeatRecv" : ISODate("2015-07-30T04:44:14.902Z"), "pingMs" : 0, "electionTime" : Timestamp(1438230801, 1), "electionDate" : ISODate("2015-07-30T04:33:21Z"), "configVersion" : 3 } ], "ok" : 1 } testrs0:SECONDARY> rs.slaveOk() testrs0:SECONDARY> db.testcoll.find() testrs0:SECONDARY> use testdb switched to db testdb testrs0:SECONDARY> db.testcoll.find() { "_id" : ObjectId("55b9942d92ad0ab98483695c"), "Name" : "test", "Age" : 60, "Gender" : "F" } { "_id" : ObjectId("55b9944892ad0ab98483695d"), "Name" : "test", "Age" : 60, "Gender" : "F" } { "_id" : ObjectId("55b9945b92ad0ab98483695e"), "Name" : "test", "Age" : 60, "Gender" : "F" } { "_id" : ObjectId("55b994ce92ad0ab98483695f"), "Name" : "test", "Age" : 50, "Gender" : "F" } { "_id" : ObjectId("55b9aa714b575261aff42f25"), "Name" : "tom", "Age" : 45, "Gender" : "G" }7、定義優先級
使用 rs.conf() 來查看 復制集配置對象 ：
testrs0:SECONDARY> rs.conf() { "_id" : "testrs0", "version" : 3, "members" : [ { "_id" : 0, "host" : "hadoop1.abc.com:27017", "arbiterOnly" : false, "buildIndexes" : true, "hidden" : false, "priority" : 1, "tags" : { }, "slaveDelay" : 0, "votes" : 1 }, { "_id" : 1, "host" : "192.168.1.4:27017", "arbiterOnly" : false, "buildIndexes" : true, "hidden" : false, "priority" : 1, "tags" : { }, "slaveDelay" : 0, "votes" : 1 }, { "_id" : 2, "host" : "192.168.1.5:27017", "arbiterOnly" : false, "buildIndexes" : true, "hidden" : false, "priority" : 1, "tags" : { }, "slaveDelay" : 0, "votes" : 1 } ], "settings" : { "chainingAllowed" : true, "heartbeatTimeoutSecs" : 10, "getLastErrorModes" : { }, "getLastErrorDefaults" : { "w" : 1, "wtimeout" : 0 } } }在hadoop3的主節點把hadoop1的優先級定義為2，讓它成為主節點
將復制集配置對象復制給一個變量（如 mycfg ）。然后通過該變量對該節點設置優先級。然后通過 rs.reconfig() 來更新復制集配置。
注意，設置優先級用這個命令mycfg.members[數組中第幾個節點].priority = 2
testrs0:PRIMARY> rs.conf() { "_id" : "testrs0", "version" : 3, "members" : [ { "_id" : 0, "host" : "hadoop1.abc.com:27017", "arbiterOnly" : false, "buildIndexes" : true, "hidden" : false, "priority" : 1, "tags" : { }, "slaveDelay" : 0, "votes" : 1 }, { "_id" : 1, "host" : "192.168.1.4:27017", "arbiterOnly" : false, "buildIndexes" : true, "hidden" : false, "priority" : 1, "tags" : { }, "slaveDelay" : 0, "votes" : 1 }, { "_id" : 2, "host" : "192.168.1.5:27017", "arbiterOnly" : false, "buildIndexes" : true, "hidden" : false, "priority" : 1, "tags" : { }, "slaveDelay" : 0, "votes" : 1 } ], "settings" : { "chainingAllowed" : true, "heartbeatTimeoutSecs" : 10, "getLastErrorModes" : { }, "getLastErrorDefaults" : { "w" : 1, "wtimeout" : 0 } } } testrs0:PRIMARY> mycfg=rs.conf() { "_id" : "testrs0", "version" : 3, "members" : [ { "_id" : 0, "host" : "hadoop1.abc.com:27017", "arbiterOnly" : false, "buildIndexes" : true, "hidden" : false, "priority" : 1, "tags" : { }, "slaveDelay" : 0, "votes" : 1 }, { "_id" : 1, "host" : "192.168.1.4:27017", "arbiterOnly" : false, "buildIndexes" : true, "hidden" : false, "priority" : 1, "tags" : { }, "slaveDelay" : 0, "votes" : 1 }, { "_id" : 2, "host" : "192.168.1.5:27017", "arbiterOnly" : false, "buildIndexes" : true, "hidden" : false, "priority" : 1, "tags" : { }, "slaveDelay" : 0, "votes" : 1 } ], "settings" : { "chainingAllowed" : true, "heartbeatTimeoutSecs" : 10, "getLastErrorModes" : { }, "getLastErrorDefaults" : { "w" : 1, "wtimeout" : 0 } } } testrs0:PRIMARY> mycfg.members[0].priority = 2 2 testrs0:PRIMARY> rs.reconfig(mycfg) { "ok" : 1 } testrs0:PRIMARY> 2015-07-30T14:34:44.437+0800 I NETWORK DBClientCursor::init call() failed 2015-07-30T14:34:44.439+0800 I NETWORK trying reconnect to 127.0.0.1:27017 (127.0.0.1) failed 2015-07-30T14:34:44.452+0800 I NETWORK reconnect 127.0.0.1:27017 (127.0.0.1) ok testrs0:SECONDARY>在hadoop1上查看，并停掉hadoop1的服務
testrs0:PRIMARY> rs.status() { "set" : "testrs0", "date" : ISODate("2015-07-30T06:51:11.952Z"), "myState" : 1, "members" : [ { "_id" : 0, "name" : "hadoop1.abc.com:27017", "health" : 1, "state" : 1, "stateStr" : "PRIMARY", "uptime" : 7780, "optime" : Timestamp(1438238074, 1), "optimeDate" : ISODate("2015-07-30T06:34:34Z"), "electionTime" : Timestamp(1438238079, 1), "electionDate" : ISODate("2015-07-30T06:34:39Z"), "configVersion" : 4, "self" : true }, { "_id" : 1, "name" : "192.168.1.4:27017", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 7780, "optime" : Timestamp(1438238074, 1), "optimeDate" : ISODate("2015-07-30T06:34:34Z"), "lastHeartbeat" : ISODate("2015-07-30T06:51:11.072Z"), "lastHeartbeatRecv" : ISODate("2015-07-30T06:51:11.375Z"), "pingMs" : 0, "configVersion" : 4 }, { "_id" : 2, "name" : "192.168.1.5:27017", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 7780, "optime" : Timestamp(1438238074, 1), "optimeDate" : ISODate("2015-07-30T06:34:34Z"), "lastHeartbeat" : ISODate("2015-07-30T06:51:11.779Z"), "lastHeartbeatRecv" : ISODate("2015-07-30T06:51:10.299Z"), "pingMs" : 0, "configVersion" : 4 } ], "ok" : 1 } testrs0:PRIMARY> quit() You have new mail in /var/spool/mail/root [root@hadoop1 ~]# service mongo stop mongo: 未被識別的服務 [root@hadoop1 ~]# service mongod stop Stopping mongod:在hadoop3查看，兩個節點還是會自動選舉主節點的
testrs0:PRIMARY> rs.status() { "set" : "testrs0", "date" : ISODate("2015-07-30T06:55:18.238Z"), "myState" : 1, "members" : [ { "_id" : 0, "name" : "hadoop1.abc.com:27017", "health" : 0, "state" : 8, "stateStr" : "(not reachable/healthy)", "uptime" : 0, "optime" : Timestamp(0, 0), "optimeDate" : ISODate("1970-01-01T00:00:00Z"), "lastHeartbeat" : ISODate("2015-07-30T06:55:16.275Z"), "lastHeartbeatRecv" : ISODate("2015-07-30T06:51:44.879Z"), "pingMs" : 5, "lastHeartbeatMessage" : "Failed attempt to connect to hadoop1.abc.com:27017; couldn't connect to server hadoop1.abc.com:27017 (192.168.1.3), connection attempt failed", "configVersion" : -1 }, { "_id" : 1, "name" : "192.168.1.4:27017", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 16000, "optime" : Timestamp(1438238074, 1), "optimeDate" : ISODate("2015-07-30T06:34:34Z"), "lastHeartbeat" : ISODate("2015-07-30T06:55:17.988Z"), "lastHeartbeatRecv" : ISODate("2015-07-30T06:55:17.988Z"), "pingMs" : 1, "lastHeartbeatMessage" : "could not find member to sync from", "configVersion" : 4 }, { "_id" : 2, "name" : "192.168.1.5:27017", "health" : 1, "state" : 1, "stateStr" : "PRIMARY", "uptime" : 16003, "optime" : Timestamp(1438238074, 1), "optimeDate" : ISODate("2015-07-30T06:34:34Z"), "electionTime" : Timestamp(1438239108, 1), "electionDate" : ISODate("2015-07-30T06:51:48Z"), "configVersion" : 4, "self" : true } ], "ok" : 1 }把hadoop1服務啟動，因為優先級設為2，故推舉它為主節點
testrs0:PRIMARY> rs.i rs.initiate( rs.isMaster( testrs0:PRIMARY> rs.isMaster() { "setName" : "testrs0", "setVersion" : 4, "ismaster" : true, "secondary" : false, "hosts" : [ "hadoop1.abc.com:27017", "192.168.1.4:27017", "192.168.1.5:27017" ], "primary" : "hadoop1.abc.com:27017", "me" : "hadoop1.abc.com:27017", "electionId" : ObjectId("55b9ca84ddeeac6a93355c18"), "maxBsonObjectSize" : 16777216, "maxMessageSizeBytes" : 48000000, "maxWriteBatchSize" : 1000, "localTime" : ISODate("2015-07-30T06:56:28.472Z"), "maxWireVersion" : 3, "minWireVersion" : 0, "ok" : 1 }8、觸發重新選舉
優先級為0的節點，無權觸發；僅參與選舉
使用的命令rs.addArb()
9、多端口復制集
應用程序需要連接多個復制集，那么每個復制集需要有不同的名字
1）為每個節點建立必要的數據文件夾：
[root@hadoop1 ~]# mkdir -pv /srv/mongodb/rs0-0 /srv/mongodb/rs0-1 /srv/mongodb/rs0-2 mkdir: 已創建目錄 "/srv/mongodb" mkdir: 已創建目錄 "/srv/mongodb/rs0-0" mkdir: 已創建目錄 "/srv/mongodb/rs0-1" mkdir: 已創建目錄 "/srv/mongodb/rs0-2" You have new mail in /var/spool/mail/root2）啟動mongod實例
第一個節點
[root@hadoop1 rs0-0]# mongod --port 27018 --dbpath /srv/mongodb/rs0-0 --replSet rs0 --smallfiles --oplogSize 128 &第二個節點
[root@hadoop1 ~]# mongod --port 27019 --dbpath /srv/mongodb/rs0-1 --replSet rs0 --smallfiles --oplogSize 128 &第三個節點
[root@hadoop1 ~]# mongod --port 27020 --dbpath /srv/mongodb/rs0-2 --replSet rs0 --smallfiles --oplogSize 128 &驗證
[root@hadoop1 ~]# netstat -tlnp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:27019 0.0.0.0:* LISTEN 15718/mongod tcp 0 0 0.0.0.0:27020 0.0.0.0:* LISTEN 15785/mongod tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1081/rpcbind tcp 0 0 0.0.0.0:28017 0.0.0.0:* LISTEN 14221/mongod tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1285/sshd tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 1157/cupsd tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1361/master tcp 0 0 0.0.0.0:44378 0.0.0.0:* LISTEN 1099/rpc.statd tcp 0 0 0.0.0.0:27017 0.0.0.0:* LISTEN 14221/mongod tcp 0 0 0.0.0.0:27018 0.0.0.0:* LISTEN 15640/mongod tcp 0 0 :::111 :::* LISTEN 1081/rpcbind tcp 0 0 :::22 :::* LISTEN 1285/sshd tcp 0 0 ::1:631 :::* LISTEN 1157/cupsd tcp 0 0 ::1:25 :::* LISTEN 1361/master tcp 0 0 :::48510 :::* LISTEN 1099/rpc.statd3）指明所需連接的端口，來通過 mongo 命令連接到某個 mongod 實例
[root@hadoop1 mongodb]# mongo --port 27018 MongoDB shell version: 3.0.5 connecting to: 127.0.0.1:27018/test 2015-07-30T16:26:01.442+0800 I NETWORK [initandlisten] connection accepted from 127.0.0.1:54185 #1 (1 connection now open) Server has startup warnings: 2015-07-30T16:19:14.667+0800 I CONTROL [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended. 2015-07-30T16:19:14.667+0800 I CONTROL [initandlisten] 2015-07-30T16:19:14.668+0800 I CONTROL [initandlisten] 2015-07-30T16:19:14.668+0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'. 2015-07-30T16:19:14.668+0800 I CONTROL [initandlisten] ** We suggest setting it to 'never' 2015-07-30T16:19:14.668+0800 I CONTROL [initandlisten] 2015-07-30T16:19:14.668+0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'. 2015-07-30T16:19:14.668+0800 I CONTROL [initandlisten] ** We suggest setting it to 'never' 2015-07-30T16:19:14.668+0800 I CONTROL [initandlisten] >最后關于
由四個節點組成的異地分布復制集有以下兩個需要注意的：
一個節點（如``hadoop4.abc.net``） 必須是一個 arbiter。這個節點可以在服務的任何機器上運行，或者在其他的MongoDB機器上運行。
我們需要決定如何分配節點。下列有3種架構類型：
在大多數情況下，由于第一種架構的易用性，我們更推薦第一種架構。
3個節點在Site A中，一個 優先級為0的節點 在Site B中，與此同時Site A中還要有個投票節點。
兩個節點在Site A，兩個 優先級為0的節點 在Site B ，同時一個投票節點在Site A。
兩個節點在Site A，一個優先級為0的節點在Site B，一個優先級為0的節點在Site C，同時一個投票節點在Site A。
在大多數情況下，由于第一種架構的易用性，更推薦第一種架構。
復制集參考
Replication Methods in the mongo Shell 命令 描述 rs.add() 為復制集新增節點。 rs.addArb() 為復制集新增一個 arbiter rs.conf() 返回復制集配置信息 rs.freeze() 防止當前節點在一段時間內選舉成為主節點。 rs.help() 返回 replica set 的命令幫助 rs.initiate() 初始化一個新的復制集。 rs.printReplicationInfo() 以主節點的視角返回復制的狀態報告。 rs.printSlaveReplicationInfo() 以從節點的視角返回復制狀態報告。 rs.reconfig() 通過重新應用復制集配置來為復制集更新配置。 rs.remove() 從復制集中移除一個節點。 rs.slaveOk() 為當前的連接設置 slaveOk 。不推薦使用。使用 readPref() 和 Mongo.setReadPref() 來設置 read preference 。 rs.status() 返回復制集狀態信息。 rs.stepDown() 讓當前的 primary 變為從節點并觸發 election 。 rs.syncFrom() 設置復制集節點從哪個節點處同步數據，將會覆蓋默認選取邏輯。復制集數據庫命令
命令 描述 replSetFreeze 防止當前節點在一段時間內選舉成為主節點。 replSetGetStatus 返回復制集的狀態報告。 replSetInitiate 初始化一個新的復制集。 replSetMaintenance 開啟活關閉維護模式，維護模式將使 secondary 進入 RECOVERING 狀態。 replSetReconfig 為已存在的復制集應用新的配置。 replSetStepDown 強制當前的 primary *降職*變為 secondary ，并觸發選舉。 replSetSyncFrom 覆蓋默認的復制來源選取邏輯。 resync 強制 mongod 重新從 master 進行初始化復制。僅在主-從模式。 applyOps 內部命令應用 oplog 在現在的數據集上。 isMaster 返回該節點的角色信息，包括是否為主節點。 getoptime 內部命令，返回optime。另外有需要云服務器可以了解下創新互聯cdcxhl.cn，海內外云服務器15元起步，三天無理由+7*72小時售后在線，公司持有idc許可證，提供“云服務器、裸金屬服務器、高防服務器、香港服務器、美國服務器、虛擬主機、免備案服務器”等云主機租用服務以及企業上云的綜合解決方案，具有“安全穩定、簡單易用、服務可用性高、性價比高”等特點與優勢，專為企業上云打造定制，能夠滿足用戶豐富、多元化的應用場景需求。
